This invention relates generally to home alarm and detection units and, more particularly, to wireless linking of detection units.
There are various types of smoke and Carbon Monoxide (CO) detecting devices that have been developed, such devices typically being battery powered, hardwired or wall-plug powered units designed to sound an alarm at the site of the detected smoke conditions. Smoke detection systems can include a plurality of detector units strategically positioned throughout the monitored area. Each of the plurality of detector units can include a detector for sensing one of a characteristic and condition within a section of the monitored area and generating a signal indicative of the monitored condition.
A signal processor or controller can be connected within each detector unit for analyzing the signal generated by the detector and upon determining if the signal is above a predetermined level generating an emergency signal. A transmitter can be provided for transmitting the emergency signal to a plurality of receiver units strategically positioned about the monitoring area. Each receiver unit includes an alarm for generating an alarm signal and thereby alert persons to the emergency situation at a position within the monitored area. The detector can be at least one of a photoelectric smoke detector, an ionization type detector, a combination carbon monoxide and smoke detector, a carbon monoxide detector, a near infrared detector and a hazard detector. There are other types of environmental condition detectors such as for example a detector for high radioactivity conditions.
However, in the past, these detection devices were not interconnected. Such devices however provide no warning to those out of the hearing range of the alarm sensing an alert condition. This obviously creates a substantial hazard to those in the same house, building or other structure who are not informed of the dangerous condition. Fire and the resulting smoke may unknowingly exist for significant periods of time in areas of buildings before the occupants are warned through conventional smoke detector systems where the detectors are not interconnected. Even with a plurality of conventional smoke detectors, occupants in remote locations of a burning building may not be able to audibly detect the local alarm horn.
A need, therefore, existed for smoke detection systems that can effectively provide early warning to building occupants in remote locations or levels away from the source of the smoke/fire or other hazardous environmental condition and can provide a means for lighted paths of egress while doing so in a cost effective and simple manner. Such a system needed to be easy to install and operate for the average user.
Smoke detectors designed for remote sensing are commonly electrically hardwired to a central enunciator/controller panel to indicate the location of the smoke within a building, which affords a plurality of remote environmental condition detectors all exchanging information through a centralized control panel. In order to connect a plurality of the prior art devices together to provide a central indication of the location of the condition sensed so as to enable the provision of specific warning to all areas or to enable steps to be taken to abate the sensed condition; it was previously necessary to physically interconnect an enunciator panel with each of the remote devices. This results in a costly system and required the use of excessive wiring along floors, walls or ceilings. Moreover, because each detection device typically generated sound at the detected location, the prior art devices were consumers of electrical power and were often unreliable and expensive. Installing and retrofitting of remote sensing smoke detection systems within buildings and residences without centralized enunciator panels is greatly facilitated with the wireless smoke detector system.
Many home fire and security alarm systems, which are often referred to as a wireless security system requires a hardwired keypad, a base station, a hardwired siren, and AC power connections. Such wireless systems actually require, therefore, considerable wiring, which makes them expensive to install and requires skilled installers. In an effort to reduce manufacturing and installation costs, many designs combined the siren into the keypad and the base station. However, these systems are not usually installed by the average consumer.
In some alarm systems, the smoke detectors are battery operated and include a small transmitter that transmits a fire alarm message to a control panel. To sound the alarm throughout the house, the control panel triggers a siren. When the alarm system is armed and an actual alarm condition is detected, prior systems sound the alarm throughout the house with one or more sirens. Each siren requires a separate installation and is usually wired in, even in so-called wireless systems. Because of the control panel installation and wiring required, prior wireless alarm systems are unduly complicated, especially for a typical homeowner to install or service, and do not have the benefits of typical hardwired systems. Accordingly, the potential of wireless home fire alarm systems has not been realized.
Battery powered smoke detectors can be designed to be completely wireless and to provide an early warning of the presence of an environmental condition of fire or smoke to persons in remote areas of a building with respect to the location of the environmental condition. The smoke detector sensing the environmental condition can emit an audible alarm of continuous tone, while emitting a frequency modulated radio signal directly to other like smoke detectors to activate their alarms in a manner indicative of the location of the smoke detector sensing the environmental alarm condition. Rechargeable light modules separate from the smoke detector are included that receive the frequency modulated radio signal from the smoke detector sensing the environmental alarm condition and illuminate paths of egress for the duration of the alarm condition.
Traditionally to allow wireless alarms to communicate to one another and discriminate against neighboring alarms a dip switch (a switch that has multiple positions, usually 8, which can generate a binary number) is used to create a unique alarm ID (address or house code). This method works fine in principle but has the drawbacks of layout issues, manually setting a random number at the factory or by the customer: cost of the switch, reliability of the switch in corrosion or manufacturing, number of unique ID's dependant on the number of switch positions and additional circuitry needed to decode the switch to cut down on number of I/O pins needed to read the switch by the microcontroller. Also dip switches usually require bottom mounting which would require the units to be removed from the ceiling during the installation period. Top mounting of a dip switch would require a removable cover or door big enough to be able to access the dip switch or change the dip switch settings with a screw driver.
Attempts around the traditional dip switch method have been to use a separate learn mode switch to put the alarm in a learn mode, rolling code encoder decoder circuitry or prepacking a set of alarms already configured to talk to one another. These attempts although eliminating the dip switch still require additional circuitry or the inflexibility of adding or removing alarms from the network.
There is a need for a wireless smoke detection and alarm system that is easy to install and resolves many of the above problems.